Optical Signal Processing

Analog-Faster-Cheaper-Better An Optical Signal Processing View Terry Turpin Chief Scientist Essex Corporation Turpin@essexcorp.com Facts • The ―The Universe‖ is analog • Human technology is still mostly analog – (did you ever see a digital bicycle) • Digital has dominated the information processing and communications world for more than three decades • Analog processing has been ignored by educational institutions • There are at least two generations of scientists and engineers that have never learned analog processing or communications technology • Analog optical processing in the past as been a small but persistent exception • Optical communications and analog optical processing are merging the same way that digital processing and digital communications did in the past Processing Overload World of Analog Signals Spread Spectrum Fiber Optic Microwave Land Lines A to Digital Stream D Radio 3,488 Tbs Television 68,955 Tbs 17,905,340 Tbs!! (2002 Data!) Telephone 17,300,000 Tbs Internet 532,897 Tbs The Information Superiority Problem So much information… so little time to process it Processing power is the key to superiority in a world market Summary of electronic information flows of new information in 2002 in terabytes … 17.7 exabytes each year, and growing “Era of Tera”* … a Digital Perspective *Pat Gelsinger, CTO Intel (Keynote address at Intel Developer Forum Feb 2004) Digital Dilemma over Power “Power density is increasing at a rate that implies that tens of thousands of watts per centimeter (w/cm2) will be needed to scale the performance of Pentium processor architecture over the next several years. But that would produce more heat than the surface of the Sun…”* *Pat Gelsinger, CTO Intel (Keynote address at Intel Developer Forum Feb 2004) … Begins the Age of Optical * Optical Processors Analog Optical Processors excel at - Images - Signals - Correlations *Pat Gelsinger, CTO Intel (Keynote address at Intel Developer Forum Feb 2004) References to Optical Processors added by Essex Corp. Analog Optical Processing Overview Optical Processing Today Faster Cheaper Cooler Better Yes Sometimes Always Sometimes Future Yes Yes Always Sometimes Measured By TIPS Bytes/$ Watts/cm2 Performance/ Application An Unclassified Success in Size, Weight and Power • Acousto-Optic Spectrometer AOS launched late 1998 on SWAS for a 2 year mission • 4 channel 1400 point Fourier transform in real time on a 1.4 GHz analog signal • Compute power is 500 Gigaflops (Sustained) for 12 Watts electrical power • Analog input eliminated the need for high speed A/D converters • Mission to study the chemical composition of interstellar clouds • SWAS would be impossible without the AOS optical computer Optical Processor/Computer? … a machine that performs mathematical functions with light rather than electrons Functions most frequently used •Fourier Transform (demultiplexing/multiplexing) •Correlation (pattern detection) •Data distribution and replication Why go to Analog Optical Processors? • Speed Advantages • Reduced size and power consumption • OEO Overhead & Cost are Excessive (optical - electrical - optical) • Natural Fit: Optical Processing for - Optical Communications - Images - Signals - Correlations • Typical improvement is a factor of 50000 Information on Light • Information is carried by the complex-valued property of light (spatial frequency, amplitude and phase) • When an information-carrying beam is passed through a special lens or coating, or interfered with another reference beam, light performs mathematical functions Massive Parallelism • Operates simultaneously on an entire wave front and more than one variable — e.g., direction, amplitude and phase • Digital systems are serial in nature • Example: A lens simultaneously acts on the entire light beam Computational Set • Analog optics can perform mathematical functions – – – – – – add copy multiply Fourier transforms correlation convolution • Operates on one- and two-dimensional arrays of numbers in parallel • A single analog optical computer ―instruction‖ might require thousands or millions of individual instructions for a conventional computer Analog Optical Computing Combines the best of both worlds: precision of electronics with massive computational power of light. Optical Computational Module 12 inches square Smaller, Lower Power, Lighter Computers Vs. Supercomputer power where it can’t go now. • Head of a missile • UAV • Mobile ICBM Defenders • Satellites Many Parallel Electronic Processors Cutting Edge Elements Materials •Photonic Crystals •Non-Linear Materials •Silicon Germanium •III-V & II-VI Materials Systems New Components •VCELS •Optical Fiber •Optical Amplifiers •SOA •EDFA •Optical Correlators •Optical Signal Processors Technology •Photon Echo •Optical Tap Delay •Solotons Example: Analog Optical Encryption • Digital Encryption – – – – ATM at 10Gbps soon No 40 Gbps on horizon Protocol specific Cost increases linearly with number of signals on a fiber • Analog Encryption – – – – 5000 Gbps on horizon (ESSEX Eclipse Module) Potential for multi-band encryption (L,C, and S) Protocol agnostic Cost is market driven and grows slowly with capacity on a fiber – 100 Teraflops for less than 10 Watts of electrical power Hyperfine Analog Optical Encryptor Point A Hyperfine Device X Gbps Device or WDM Devic e Phase Key Control Computer Sub-channels X Gbps … Reflective Phase Modulator Array C Band Comms Device Phase Key Control Computer Analog Encoding ―key‖ Point B X Gbps Hyperfine Device X Gbps Device or WDM Devic e Analog Decoding ―key‖ Sub-channels … Reflective Phase Modulator Array C Band Comms Device How Does it Work? Input Transmitted Scrambled Photons Recovered Simulated Data Terabit Security – Cost Perspective * * ** ** *Assumes that aggregate bandwidths above 10 Gbps will be encrypted using multiple 10 Gbps encryptor pairs – 1 pair per wavelength ** Estimated costs are based on a multiplexed optical signal with aggregate bandwidth as indicated, and single optical encryptor pair per optical link Additional Advantages • Analog optical processing provides an alternate approach to thinking about problems • This alternate approach often leads to solutions that are radically different and sometimes better • For example, to implement continuous scale change and Fourier transforms on data that has not been sampled or digitized • Enable solutions to problems that are thought to be too complex to solve economically • In supercomputing applications the improvement is about a factor of 50000 Summary • Analog is faster, cheaper and better • Examples are – Separating signal channels in frequency – Optical Encryption – Optical Communications – Optical Signal Processing • Analog is a key technology • Analog optical technology will force analog electronics because of the A/D conversion limitation • In optical communications, analog encryption and wavelength routing will provide growth at low cost per terabit